PSI - Issue 78

Filippo Campisi et al. / Procedia Structural Integrity 78 (2026) 1197–1204

1203

Table 3. EDP max and main vibration periods for the case study models. Case

AB AB+B R0 R0+B R1 R1+B R2 R2+B

EDP max (mm)

1.3

1.8

67

67

6.0

6.0

2.5

2.5

T 1 (s)

0.05

0.06 0.038 0.043 0.038 0.043 0.038 0.043

4.3. Analysis results Multiple-stripe analyses were carried out for the considered cases. For each model, the ground motion selection was updated by conditioning the sets to the spectral accelerations at the relevant vibration periods. The target code spectrum shown in Fig. 4a was used as the reference. For the sake of brevity MSA results are illustrated in Fig. 8 only for specimens AB+B and R0+B. In the same diagrams the EDP max are shown for the different case studies. As can be observed, a large increase in the average IM range is obtained for the reinforced case with respect to the as-built condition. The fragility curves are illustrated in Fig. 8 for all the considered case studies. Overall, it is evident that due to the strength and EDP max increment associated with the reinforcement the spectral accelerations at a 50% collapse probability had an increment from two to six times in the retrofitted cases. The backfill material played a dual role. While it had a favorable effect in the non-reinforced cases due to its stabilizing action, its presence increased the fragility of the retrofitted vaults, as the added mass had a major influence. The strength limitation due to the debonding largely reduced the EDP max and the resistance of the retrofitted vaults. However, even in the worse simulated conditions of 1/3 of the nominal GFRP strength, the S a (T 1 ) at 50% collapse probability was increased by at least two times. The average collapse S a (T 1 ) values are illustrated in Table 4.

(a)

(b)

Fig. 8. Multiple Stripe Analysis results: (a) AB+B model; (b) R0+B model.

Fig. 9. Fragility curves for the considered cases studies.

Table 4. Average collapse S a (T 1 ) values. Case

AB AB+B R0 R0+B R1 R1+B R2 R2+B 0.56 3.16 2.66 1.29 0.96 1.12 0.84 0.46

S a (T 1 ) avg [g]